From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Tue, 11 Sep 2001 07:57:02 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Tue, 11 Sep 2001 07:56:51 -0400 Received: from penguin.e-mind.com ([195.223.140.120]:9250 "EHLO penguin.e-mind.com") by vger.kernel.org with ESMTP id ; Tue, 11 Sep 2001 07:56:34 -0400 Date: Tue, 11 Sep 2001 13:57:35 +0200 From: Andrea Arcangeli To: Dipankar Sarma Cc: linux-kernel@vger.kernel.org, Paul Mckenney Subject: Re: 2.4.10pre7aa1 Message-ID: <20010911135735.T715@athlon.random> In-Reply-To: <20010911172301.A2069@in.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20010911172301.A2069@in.ibm.com>; from dipankar@in.ibm.com on Tue, Sep 11, 2001 at 05:23:01PM +0530 X-GnuPG-Key-URL: http://e-mind.com/~andrea/aa.gnupg.asc X-PGP-Key-URL: http://e-mind.com/~andrea/aa.asc Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Sep 11, 2001 at 05:23:01PM +0530, Dipankar Sarma wrote: > In article <20010911131238.N715@athlon.random> you wrote: > > many thanks. At the moment my biggest concern is about the need of > > call_rcu not to be starved by RT threads (keventd can be starved so then > > it won't matter if krcud is RT because we won't start using it). > > > Andrea > > I think we can avoid keventd altogether by using a periodic timer (say 10ms) > to check for completion of an RC update. The timer may be active > only if only if there is any RCU going on in the system - that way > we still don't have any impact on the rest of the kernel. the timer can a have bigger latency than keventd calling wait_for_rcu so it should be a loss in a stright bench with light load, but OTOH we only care about getting those callbacks executed eventually and the advantage I can see is that the timer cannot get starved. Andrea